TLD5095EL_15 Datasheet, PDF (16/35 Pages) Infineon Technologies AG – Multitopology LITIX Power DC/DC Controller IC

Infineon® LITIX™ Power
TLD5095EL
Enable and Dimming Function
7
Enable and Dimming Function
Description
The enable function powers on or off the device. A valid logic low signal on enable pin EN/PWMI powers off the
device and current consumption is less than 10 µA. A valid logic high enable signal on enable pin EN/PWMI
powers on the device. The enable function features an integrated pull down resistor which ensures that the IC
is shut down and the power switch is off in case the enable pin EN is left open.
In addition to the enable function described above, the EN/PWMI pin detects a pulse width modulated (PWM)
input signal that is fed through to an internal gate driver. The internal gate driver outputs the same PWM signal
on the PWMO pin to an external n-channel enhancement mode MOSFET for PWM dimming an LED load. PWM
dimming an LED is a commonly practiced dimming method to prevent color shift in an LED light source.
Moreover the PWM output function may also be used for to drive other types of loads besides LED.
The enable and PWM input function share the same pin. Therefore a valid logic low signal at the EN/PWMI pin
needs to differentiate between an enable power off signal or an PWM low signal. The device differentiates
between an enable off command and PWM dimming signal by requiring the signal at the EN/PWMI pin to stay
low for a minimum of 8 ms.
IN
14
Enable
LDO
IVCC
1
Microcontroller
EN / PWMI
13
Enable / PWMI
Logic
Enable
Gate
Driver
SWO
2
PWMI
Gate
Driver
PWMO
5
EN_PWMI_BlockDiagram.svg
Figure 7-1 Block Diagram and Simplified Application Circuit Enable and LED Dimming
Data Sheet
16
Revision 1.4
2015-03-11